Systems and methods for added authentication in distributed network delivered half-duplex communications

ABSTRACT

In half-duplex communications over a wireless network, a user from a private organisation sends the request for half-duplex communication through a private server controlled by the private organisation. The private server sets up a private account with the wireless carrier and the user communicates via the private account.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/523,466 filed Nov. 19, 2003.

TECHNICAL FIELD

The patent application relates generally to systems and methods forhalf-duplex communications over wireless networks, such as Push-to-Talk™over Cellular (PoC).

DESCRIPTION OF THE RELATED ART

Network delivered half-duplex communications, such as those provided byPoC architectures for example, provide wireless devices with the abilityto communicate with each other in a half-duplex manner, much likewalkie-talkies, but over a network.

Referring to FIG. 1, there is shown a conventional PoC architecturedefined by 3GPP standards bodies for implementing half-duplexcommunications. The specification under development from the Open MobileAlliance™ is: OMA-AD_PoC-V1_(—)0-20031017-D andOMA-AD_PoC-V1_(—)0-20041005-D. Both of these specifications areincorporated herein by reference in their entirety. In the conventionalarchitecture, the components of the PoC architecture are located withinthe carrier's network or a directly related third-party serviceprovider. A PoC client device 101 is shown accessing a carrier network100 for half-duplex communication through wireless access network 103.Within the carrier network 100, there is a SIP/IP Core 102. Some of thefunctions of the SIP/IP Core include routing the SIP signalling betweenthe PoC client device, authenticating and authorising PoC users, andcharge reporting. The carrier network also has a Group and ListManagement Server (GLMS) 104, PoC server 106 and presence server 108.The GLMS server 104 manages groups, contact lists and access lists. ThePoC server 106 functions include, among other things, SIP and groupsession handling, policy control for access to groups, group sessioncontrol, and access control. The presence server 108 manages presenceinformation and combines various presence-related information into asingle presence document.

As shown in FIG. 1, in the conventional architecture, a POC client 101of a wireless network accesses the PoC element through the network's POCserver 106, the network's SIP/IP core 102 or the network's GLMS 104. Theconventional architecture is network operator centric, where a singleoperator or carrier runs all necessary components to make the solutionfunction. All identities used for conversations and group chats arepublicly available to other PoC users through the carrier's Group andList Management Server (GLMS) 104. Requests for conversations and groupchats are made to the carrier's SIP Core 102 using only SIP identities.The ability for latecomers to join a chat session is also supported.These requirements mean that the ability to create PoC sessions is notvery private and eavesdropping could become commonplace.

SUMMARY

In one aspect, there is provided a method comprising: a wireless userdevice interacting with a private authentication element to obtainidentities of private user devices; the wireless user device sending arequest for a PoC (Push-to-Talk™ over Cellular) session to a CHDP(carrier half-duplex processing element), the request identifying atleast one invitee private user device; the CHDP sending a request forauthentication of the at least one invitee private user device to theprivate authentication element; the private authentication elementauthenticating the at least one invitee private user device and sendingan authentication response to the CHDP indicating whether or not the atleast one invitee private user device is authenticated; the CHDP sendinginvitations for the PoC session to authenticated invitee private userdevices and receiving acceptances/rejections; and the CHDP setting upthe PoC session for authenticated users that have accepted theinvitation.

In a second aspect, there is provided a method comprising: a privateauthentication element interacting with a wireless user device toestablish private identities of private user devices; the privateauthentication element receiving a request for authentication of theprivate identities from a carrier half-duplex processing elementassociated with a requested a PoC session; the private authenticationelement authenticating the private identities; and the privateauthentication element sending an authentication response to the carrierhalf-duplex processing element indicating whether or not the privateidentities are authenticated.

In a third aspect, there is provided a method in a wireless user devicecomprising: the wireless user device interacting with a privateauthentication element to obtain private identities of private userdevices; and the wireless user device sending a request for a PoCsession identifying at least one invitee private user device to a CHDP,the request indicating to the CHDP to perform authentication of the atleast one invitee private user device with the private authenticationelement.

In a fourth aspect, there is provided a carrier half-duplex processingelement (CHDP) comprising: a first input for receiving requests from aclient device for a PoC session with at least one private user device inresponse to which the CHDP generates an authentication request forauthentication of private identities of private user devices; an outputfor sending the authentication request to a private authenticationelement; a second input for receiving an authentication response fromthe private authentication element; and wherein in the event ofsuccessful authentication, the CHDP invites the private user devices toparticipate in the PoC session and sets up a half-duplex communicationssession between devices that accept.

In a fifth aspect, there is provided a system for authenticating privateusers from a private network when conducting PoC communications over acarrier network, the system comprising: a carrier processing elementconfigured to receive a request for a PoC session from a wireless userdevice, to send an authentication request of an identity of at least oneprivate invitee user device to a private authentication element, to sendan invitation for the PoC session to the at least one private inviteeuser device if an authentication is response received from the privateauthentication element, and to set up the PoC session between thewireless user device and the at least one private invitee user device;and a private authentication element configured to establishauthenticated identities of private user devices, to receive theauthentication request from the carrier processing element, toauthenticate the identities and to send the authentication response backto the carrier processing element indicating whether or not theidentities are authenticated.

In an embodiment, a PoC solution provides a corporate authenticationservice that proxies both GLMS and PoC Server requests to ensure that acorporation authenticates all participants in a PoC Session. Thisauthentication ensures that all PoC users have been authenticated by thecorporation and creates private and authenticated PoC Sessions.

In another embodiment, a network-centric PoC Server extends itsfunctionality to include an authentication step. This authenticationstep can be offered by a corporate-based GLMS component via anetwork-centric GLMS component with an authentication component ordirectly to the corporate-based GLMS.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in greater detail with reference tothe accompanying diagrams, in which:

FIG. 1 is a block diagram of a conventional PoC architecture definedwithin the 3GPP standards bodies for implementing PoC;

FIG. 2 is a block diagram of a general architecture for providingauthentication of half-duplex users;

FIG. 3 is a flowchart showing a method of authenticating half-duplexcommunication users;

FIG. 4 is a block diagram of a first proxy system used in conjunctionwith a carrier-based PoC service;

FIG. 5 is a flowchart of a method of authenticating PoC users within aPoC architecture;

FIG. 6 is a block diagram of a second proxy system used in conjunctionwith a carrier-based PoC service; and

FIG. 7 is a block diagram of a third proxy system used in conjunctionwith a carrier-based PoC service.

DETAILED DESCRIPTION OF THE DRAWINGS

It would be advantageous to have authentication for half-duplexcommunications services such as PoC provided to corporate users. Thecurrent architectures for half-duplex communication over wirelessnetworks, such as PoC, do not address the corporate requirement forauthentication. It would be advantageous to authenticate the users in ahalf-duplex chat session, such as PoC, or to create authenticatedgroups.

In some settings it would be advantageous to be able to limit ahalf-duplex conversation to employees of a specific company orindividuals that are part of a specific deal being formed. Byauthenticating the user who initiates the conversation and each invitee,all participants in the conversation can be confident that when a usersays he or she is ‘Person X’, they are truly ‘Person X’ as confirmed bysome authority, such as a corporate Security Identity Name Server or anauthenticated corporate GLMS.

FIG. 2 shows a general architecture for authenticating half-duplexusers. A carrier network 200 is shown. The carrier network has wirelessaccess network element 210 and CHDP (carrier half-duplex processingelement) 212 generally representing any element(s) within the carriernetwork that participates in the delivery of network providedhalf-duplex communications. Also shown is a private network 201 thatmight be operated by a private organization for example. The privatenetwork 201 is “private” in the sense that it is under the control of adifferent party than the carrier network 200. The private network 201includes a private authentication element 202 that authenticates usersfrom the private network 201 for participation in half-duplexcommunications. The private authentication element is one or more ofhardware and software that can be added to a distinct component or astandard component. In some embodiments the private authenticationelement sits on a secure identity server such as a GLMS. Forillustration purposes the private authentication element 202 is depictedwithin the private network 201. However, in some embodiments the privateauthentication element 202 is physically located outside the premises ofthe private network 201. The private network can be any set of users,such as a corporation with employees as its users.

A set of regular half-duplex wireless user devices (UD) is indicated at206. A “regular half-duplex wireless user device” is a device equippedto function as a regular half-duplex client. Half-duplex functionalityis provided to these clients in a normal manner by the CHDP 212. Alsoshown is a set of private half-duplex wireless user devices 204associated with the private network 201. A private half-duplex device isa device equipped to function as a private half-duplex client.Half-duplex communications are provided to the private half-duplexwireless user devices 204 by the CHDP 212 in co-operation with theprivate authentication element 202 as detailed below. Examples ofwireless user devices include hand-held wireless devices, wirelessenabled laptop computers, wireless enabled desktop computers,Smartphones, wireless enabled PDAs (Personal Digital Assistants), andcellular handsets.

In some embodiments, a given wireless user device is equipped tofunction in multiple modes of operation. In some implementations, agiven “private wireless user device” has mode(s) of operation that allowthe device to operate in a similar manner to regular wireless userdevices. A given wireless user device might be equipped with both theregular half-duplex client and the private half-duplex clientcapabilities. Such a wireless user device might switch between being a“regular wireless user device” and a “private wireless user device”dynamically. Such a wireless user device has two user identifiers—onefor regular use and one for private use. Such a wireless user device canthen initiate/participate in a regular half-duplex communication thatwould be processed by CHDP in a normal manner, or couldinitiate/participate in the added authentication features of thehalf-duplex communication described below.

By way of overview, in operation, upon receipt of a request forauthenticated half-duplex communication from a private wireless userdevice 204, the CDHP routes an authentication request to the privateauthentication element 202 of the private network 201. The privateauthentication element 202 authenticates the user who initiates ahalf-duplex conversation and the invitees and informs the CDHP of theresult. If authentication is successful, the half-duplex communicationsis made possible. In some embodiments, a user selects the invitees froma list of possible invitees that was created in co-operation with theauthentication element 202.

FIG. 3 is a flow chart showing a method of authenticating wireless userdevices in half-duplex communications within the architecture shown inFIG. 2. In general terms, the method begins with a private user decidingto conduct an authenticated half-duplex communication session using awireless user device (Step 401). In some embodiments this is achieved byselecting an authentication mode from a menu presented on the wirelessuser device. Another option on such a menu can include a regularhalf-duplex session. Once an authenticated half-duplex session ischosen, then an invitation is created by the wireless user device forauthenticated half-duplex communications with a set of one or moreinvitees having private invitee user devices (Step 402). The invitationwill trigger the access network to route an authentication request tothe private authentication element. At Step 403, the authenticationrequest is routed to the private authentication element through thecarrier network. The private authentication element authenticates thewireless user devices and the private invitee user devices (Step 404).Any type of authentication may be implemented here. In one embodiment,Step 404 involves verifying that all of the identities of the user andthe invitees are on a predetermined list prepared by the privateorganisation. The private authentication element sends an authenticationresponse back to the CHDP indicating whether or not the wireless userdevice and private invitee user device have been authenticated (Step406). If the wireless user device and the private invitee user devicesare authenticated, the invitation is sent by the CHDP to the privateinvitee user devices to join in the half-duplex communication session(Step 410). If at Step 406, it is determined that the wireless userdevice or one of the private invitee user devices is not authenticated,a failure signal is sent to the wireless user device through the carriernetwork.

In some embodiments of the architecture and method shown in FIGS. 2 and3, the identities of the user and invitees sent to and from the privateauthentication element 202 are encrypted. Furthermore, in someembodiments, the users are clients of more than one wireless carriernetwork.

In some embodiments, the verification of a group by the privateauthentication element confirms for the invitees that the request forhalf-duplex communication has been authenticated for the entire group.

In the embodiments that follow, the private organisation is described asa corporation. However, the embodiments equally apply to anyorganisation wishing to authenticate its users of half-duplexcommunications. The wireless user device in the embodiments that followis described as a PoC client device. More generally, embodiments areapplicable to any wireless user device and system, as previouslydefined, with half-duplex capabilities. Furthermore, while half-duplexcommunication is preferred, other embodiments are applicable to instantcommunications generally. These may be half-duplex, full duplex or textbased.

Turning to FIG. 4, there is shown an illustration of a first embodimentfor a proxy-like PoC architecture used in conjunction with acarrier-based PoC service. FIG. 4 shows a PoC client device 53 withadded authentication features that accesses a wireless carrier networkand a corporate GLMS 14, which is within a corporate firewall 99, ifpresent. The wireless carrier includes a SIP/IP core 52, a GLMS 54, aPoC server 56, and a Presence Server 58. The PoC client device 53 is incommunication with the corporate GLMS 14 via interface 61, the SIP/IPcore 52 via interface 66, the wireless carrier GLMS 54 via interface 62and the wireless network PoC server 56 via interface 68. The SIP/IP core52 is in communication with the PoC server 56 via interface 67 and thePresence Server 58 via interface 65. The Presence Server 58 also hasinterfaces with the GLMS 54 (interface 63) and the PoC server 56(interface 69). The carrier GLMS 54 communicates with the PoC server 56via interface 64. The corporate GLMS also has an interface 70 with thePoC server 56. A wireless access network 51 is shown, through which thePoC client device accesses the carrier network components. A WAN accessnetwork 59 is also shown, through which the corporate GLMS 14 accessesthe carrier network components. In some embodiments, the interfaces inthis architecture are standard interfaces, such as those described inthe OMA standards referred to above, such as some form of TCP/IP orUDP/IP communications over a data portion of a carrier's network.Examples include XML, HTTP, SIP or RTP over a TCP/IP or UDP/IP typecommunication stacks.

The embodiment shown in FIG. 4 provides a corporate-based GLMS 14functioning in-line with the existing PoC system within the carriernetwork's domain. The corporate GLMS 14 is used for authentication ofattendees to a PoC chat session. The corporate GLMS 14 is also used bythe corporation to create private authenticated identifies for eachcorporate user. These authenticated identities can be used withoutdisclosing the true identity to the general public or to the carriernetwork directly. In some embodiments this is achieved withauthentication keys and certificates, which can be seen by other PoCusers without compromising their integrity.

Preferably, the corporate GLMS 14 uses standard interfaces tocommunicate with PoC components, such as those discussed in the OMAstandards referred to above. In this way the corporate GLMS 14 will beable to stay in-step with ongoing standards definitions for theseinterfaces. However, in some embodiments a proprietary protocol can beused. In some embodiments, the link between the existing PoC networkcomponents and the corporate GLMS 14 is through a traditional WANinterface 59.

The corporate GLMS 14 makes itself known to the existing network PoCcomponents so that a relationship can be established and there is anindication of what domain is supported by the corporate GLMS 14.

The PoC server 56 communicates with the corporate GLMS 14 toauthenticate the requesting user device and/or the invitees undercircumstances defined for a given implementation. In some embodimentsthis authentication is triggered by the requesting user device having anaddress within a specified domain. This authentication can be triggeredby the invitee(s) having an address within a specified domain. Thisauthentication can be triggered by a flag or other indication in therequest.

Thus, in a specific example, the corporate GLMS 14 registers with thePoC server 56 and the carrier GLMS 54 for a specific domain type spaceand users that request groups or identities that are within this domainspace are confirmed through the private GLMS. For example, users with aSIP address of SIP:USERX@companyY.NetworkZ.COM are supported by thecorporate GLMS called “CompanyY” and the corporate GLMS′ address on theInternet is X.X.X.Y.

The corporate GLMS 14 is a part of an identity and authorizationprocess. In the conventional system, the PoC Server 56 assumes the SIPidentities are valid. SIP uses a Uniform Resource Identifier (URI) toidentify and authorize valid mobile stations within the network. It isalso been proposed that E.164 (MS-ISDN or phone numbers) can be used toaddress and verify identity. According to one aspect, this authorizationis complemented by a secondary authorization by the corporate GLMS 14.In this role the corporate GLMS 14 acts like a ‘AAA’ server(Authentication, Authorization and Accounting). This reduces some of thecomplications of placing this function within the carrier network'sinfrastructure directly.

Turning now to FIG. 5, there is shown a flowchart of a method ofauthenticating the PoC. The assumption is that the users are corporateusers who want to conduct an authenticated PoC session. If the users areregular users or a corporate user operating as a regular user, then thecall is processed normally (i.e. in a conventional manner). The methodbegins with a corporate user having a PoC client device with addedauthentication features obtaining PoC identities (Step 502). In someembodiments these PoC identities are used to populate an address book.The PoC identities may be identified as requiring authentication or not.The PoC identities requiring authentication are established with thecorporate GLMS (Step 503). In the architecture of FIG. 4, this is doneover interface 61. Using the PoC client device 53, the corporate userinitiates an authenticated PoC session (Step 504). In some embodiments,this is done by selecting an authentication node from a menu.Alternatively, it may be done by selecting authenticated identities asinvitees. The PoC client device 53 creates a SIP invitation (Step 506).The invitation will include SIP identities and authentication tagsobtained from the corporate GLMS 14. The SIP/IP core 52 handles theinvitation (Step 508). This involves some SIP processing, picking amedia or PoC server 56 and sending the invitation to the PoC server. ThePoC server 56 will validate the PoC request with a GLMS component andidentify the session as a regular or authenticated session (Step 510).Based on attributes of the PoC request, the authentication request isrouted to the corporate GLMS 14 (Step 512) by the PoC server, where thecorporate user and invitees are authenticated and the invitation issecured (Step 514). An example of an attribute is a security key.Examples of methods of authentication include public key or symmetrickey technology. Based on the success of authentication, half-duplexcommunications are authorized or not (Step 515). The signal indicatingwhether or not that authentication was successful is sent back to thePoC server through interface 70. If authorized, the invitation is sentto the invitees (Step 516). Once the invitees have accepted the PoCserver will transition the connection to a media server to exchangevoice data. If authentication fails, the corporate GLMS sends a responseto the PoC server over interface 70 indicating that authentication hasfailed.

In another embodiment, the method of FIG. 5 can be adapted toauthenticate new participants before they join an authenticatedhalf-duplex conversation that is in progress.

Further, in some embodiments, a corporate identity is sent by the PoCclient device 53 over the interface 61 to the corporate GLMS 14 in theprocess of obtaining identities of private wireless user devices and tothe PoC Server 56 via interface 68 with PoC session requests. Thiscorporate identity is preferably encrypted using one of many availableencryption techniques including but not limited to PGP, S/MIME, TripleDES, AES, ECC using either public keys or private symmetric keys. Thiscorporate identity field is encoded by the PoC client device 53 such asa mobile station and can only be decoded by the corporate GLMS component14 as no other entity has the necessary information.

For example across a standard Im interface between a PoC client deviceand a GLMS, the HTTP command might look like the following: GEThttp://glms.networkA.com/script?action=create_list_set&owne r=sip

3Gary.mousseau

40gprs.ca&list_displayname=Private Co- Workers HTTP/1.1 Authorization:Digest username=“u45671234”, realm=“glms.rogers.ca”,nonce=“dcd11b7702ee4f0e8b11d0f600bfb0c093”,uri=“http://glms.networkA.com/script?action=create_list_set &owner=sip

3Gary.mousseau

40gprs.ca&list_displayname=Co- Workers”,response=“e988c992a9123456e42c8ee200cec7f6”,cnonce=“dcd99agsjjkla123452dd2f0e8b1”,opaque=“12345ccdd03ebaf9f0171e9517f40e41”, qop=auth-int, nc=00000001

When sent directly to the corporate GLMS component 14 by the PoC clientdevice via interface 61 (as shown in FIG. 4), the command would bechanged in several ways to appear as follows: GEThttp://glms.companyA.com/script?action=create_list_set& owner=sip

3Gary.mousseau

40gprs.ca&list_displayname= Private&private-ID=“T8&

$34

$#4” Co-Workers HTTP/1.1 Authorization: Digest username=“u45671234”,realm=“glms.rogers.ca”, private_GLMS=“glms_Accounting.CompanyX.com”,nonce=“dcd11b7702ee4f0e8b11d0f600bfb0c093”,uri=“http://glms.networkA.com/script?action=create_list_set &owner=sip

3Gary.mousseau

40gprs.ca&list_displayname=Co- Workers”,response=“e988c992a9123456e42c8ee200cec7f6”,cnonce=“dcd99agsjjkla123452dd2f0e8b1”,opaque=“12345ccdd03ebaf9f0171e9517f40e41”, qop=auth-int, nc=00000001

The addition of a new domain name ‘glms.companyA.com’ allows the HTTPrequest to be routed directly to the corporate GLMS 14 through thepublic Internet access point offered by most carriers today viainterface 61.

Another embodiment involves extended addressing made to SIP requeststhat get passed along to the PoC server 56 from the PoC client device,as in FIG. 4. For example within the standard SIP and standard interfaceIk (the interface between a PoC server and a GLMS) the following wouldbe normal information exchanged: INVITE sip:bob@example.org SIP/2.0 To:<bob@example.org> From: <carol@example.org>;tag=xyz Call-Id:7@c.example.org CSeq 1 INVITE Contact: <sip:carol@c.example.org>

From a PoC client device 53 such as a mobile station modified to workwith a corporate GLMS 14 the SIP invitation might look like thefollowing: INVITE sip:bob@example.org “ARZ$

E89@#” SIP/2.0 To: <bob@example.org> “JUIRT8

$!IJP” From: <carol@example.org.> “M6

$PQWE9 (+”; tag=xyz Call-Id: 7@c.example.org CSeq 1 INVITE Contact:<sip:carol@c.example.org>

The presence of the extended address is an indication to the PoC Server56 that an extended authentication is required for this invitation. Ifthis is the case, the PoC Server 56 sends the encrypted identities tothe corporate GLMS 14 via interface 70 for decryption andauthentication. The SIP authentication response that is returned to thePoC server indicates which of the participants are authorized toparticipate in the PoC Session. In another embodiment, the SIP Requestauthorization header is used to carry credentials of the user. In thissituation portions of the header are opaque to all elements ofarchitecture, except for the corporate GLMS 14, meaning those portionscan be seen by the carrier network but not understood.

Turning to FIG. 6, there is shown an illustration of a second proxyarchitecture used in conjunction with a carrier-based PoC service. Thisembodiment is similar to the one shown in FIG. 4, except the PoC clientinterface traffic sent to the corporate GLMS 14 originates from thecarrier network's GLMS 54. The only difference over the structure shownin FIG. 4 is that there is no interface from the PoC client device tothe corporate GLMS 14 and there is an interface 71 between the corporateGLMS 14 and the carrier GLMS 54.

In this illustration there are many choices for the interface protocolthat is used between the carrier GLMS 54 and the corporate GLMS 14. Insome embodiments, this link labelled 71 could carry standard Im trafficand Ik traffic (where Im is defined as a standard interface between awireless user device and a GLMS and standard Ik is defined as a standardinterface between a PoC server and a GLMS), or it could use aproprietary protocol developed specifically to carry authenticationrequests. One choice could be to mirror the interface 62 between the PoCclient device 53 and the carrier GLMS 54. In some embodiments, thisinterface 62 uses XML over HTTP, a simple protocol and addressing methodthat could be mirrored from the PoC client device 53 all the way to thecorporate GLMS 14. In this way the configuration of the PoC clientdevice 53 could be simplified and there would be less work needed on thePoC client device 53 to ensure information is relayed to the corporateGLMS 14. For example each PoC client device could be configured asneeding corporate GLMS 14 support as they are deployed via a specificcorporation. Since the interface between the PoC client device 53 andthe corporate GLMS 14 is unique to this embodiment, it is possible tomake the interface any desirable choice other than HTTP. As discussedwith reference to FIG. 4, the corporate GLMS 14 will make itself knownto the carrier network.

In this embodiment, the traffic from the PoC client device 53, such as amobile station, to the carrier GLMS 54 (interface 62) can be used tocarry the information needed for the corporate GLMS 14. As discussedwith reference to FIG. 4, a modified HTTP header could carry theencrypted identities to indicate to the carrier GLMS 54 that furtherauthentication is required.

This embodiment has the advantage that the creation of groups and listscan still operate as normal. For those groups and lists being created bycorporate users, encrypted private identities would also accompany thecreation request. When this does happen and private identities arepresent, the carrier GLMS 54 recognizes the need for corporate-basedauthentication and uses interface 71 to acquire that authentication. Forall those members of the group that get approval they can be added tothe group or list being created. An authentication response is sent backto the carrier GLMS 54 via interface 7.

Turning to FIG. 7, there is shown an illustration of a third proxyarchitecture used in conjunction with a carrier-based PoC service. Thisembodiment is similar to the first and second embodiments shown in FIGS.4 and 6. The only difference from FIG. 6 is that there is no interfacebetween the corporate GLMS 14 and the network PoC server 56.

In this embodiment all traffic to the corporate GLMS 14 proceeds throughthe carrier GLMS 54 via interfaces 62 and 71. All requests forauthentication pass through the carrier GLMS 54 and to the corporateGLMS 14 as indicated.

In this embodiment all corporate authentication requests are routedthrough the carrier GLMS 54. This requires only one special link betweenthe carrier GLMS 54 and the corporate GLMS 14. In some embodiments, thislink labelled 71 could carry standard Im traffic and Ik traffic (whereIm is defined as a standard interface between a wireless user device anda GLMS and Ik is defined as a standard interface between a PoC serverand a GLMS), or it could use a proprietary protocol developedspecifically to carry authentication requests. For example the use of anIm interface to the corporate GLMS component 14 could be achieved. Thestandard Im interface is described and defined to use an XML formattransmitted using HTTP. In the discussion of FIG. 4, various ways tomodify the HTTP header information so that the carrier GLMS 54 couldeasily recognize and forward the encrypted identities to the corporateGLMS 14 for further authentication were described.

In the illustration depicted in FIG. 7, there are many choices for theinterface protocol that is used between the carrier GLMS 54 and thecorporate GLMS 14. One of these choices could be to use the same type ofinterface as between the PoC client 53 and the carrier GLMS 54. Thisembodiment has the advantage of reducing the requirements for the PoCServer 56 as an interface to the corporate GLMS 14 is not required. Forthose PoC client devices that indicate a corporate connection, PoCsession requests are verified through the carrier GLMS 54 and thenrelayed on to the corporate GLMS 14 via interface 71. As discussed withreference to FIG. 4, the corporate GLMS will have made itself known tothe carrier network and the SIP addresses used by the PoC client device53 will indicate to the carrier GLMS 54 that they are within the domainsupported by the corporate GLMS 14. Only if a positive feedback isreturned to the carrier GLMS 54 over interface 71, will PoC invitationsbe extended to the one or many invitees.

The above-described embodiments of the present invention are intended tobe examples only. Those of skill in the art may effect alterations,modifications and variations to the particular embodiments. For example,in other embodiments the private authentication element sits on a serverwithin the carrier network.

1. A method comprising: a wireless user device interacting with aprivate authentication element to obtain identities of private userdevices; the wireless user device sending a request for a PoC(Push-to-Talk™ over Cellular) session to a CHDP (carrier half-duplexprocessing element), the request identifying at least one inviteeprivate user device; the CHDP sending a request for authentication ofthe at least one invitee private user device to the privateauthentication element; the private authentication elementauthenticating the at least one invitee private user device and sendingan authentication response to the CHDP indicating whether or not the atleast one invitee private user device is authenticated; the CHDP sendinginvitations for the PoC session to authenticated invitee private userdevices and receiving acceptances/rejections; and the CHDP setting upthe PoC session for authenticated users that have accepted theinvitation.
 2. The method of claim 1 further comprising the privateauthentication element registering with the CHDP to performauthentication for a particular domain.
 3. The method of claim 1 whereinsending a request comprises sending the request to a PoC server of theCHDP.
 4. The method of claim 3 wherein the CHDP further comprises acarrier GLMS (Group List Management Server).
 5. The method of claim 1,wherein interacting further comprises using a carrier GLMS as anintermediary.
 6. The method of claim 1 wherein sending an authenticationresponse uses a carrier GLMS as an intermediary.
 7. The method of claim1 wherein the private authentication element is a GLMS.
 8. The method ofclaim 1 further comprising the wireless user device encrypting anidentity of the at least one invitee private user device.
 9. A methodcomprising: a private authentication element interacting with a wirelessuser device to establish private identities of private user devices; theprivate authentication element receiving a request for authentication ofthe private identities from a carrier half-duplex processing elementassociated with a requested a PoC session; the private authenticationelement authenticating the private identities; and the privateauthentication element sending an authentication response to the carrierhalf-duplex processing element indicating whether or not the privateidentities are authenticated.
 10. The method of claim 9 whereininteracting comprises the private authentication element interactingwith the wireless user device via a carrier GLMS.
 11. The method ofclaim 9 wherein: receiving comprises receiving the request from a PoCserver; sending comprises sending the authentication response to the PoCserver.
 12. The method of claim 11 wherein: receiving comprisesreceiving the request from the PoC server via a carrier GLMS; andsending comprises sending the authentication response to the PoC servervia the carrier GLMS.
 13. The method of claim 9 wherein the privateauthentication element is a GLMS.
 14. The method of claim 9 furthercomprising the private authentication element registering with thecarrier half-duplex processing element to perform authentication for aparticular domain.
 15. A private authentication element configured toperform the method of claim
 9. 16. The authentication element of claim15 comprising a private GLMS.
 17. A computer readable medium withcomputer readable code stored thereon for implementing the method ofclaim
 9. 18. A method in a wireless user device comprising: the wirelessuser device interacting with a private authentication element to obtainprivate identities of private user devices; and the wireless user devicesending a request for a PoC session identifying at least one inviteeprivate user device to a CHDP, the request indicating to the CHDP toperform authentication of the at least one invitee private user devicewith the private authentication element.
 19. The method of claim 18wherein interacting comprises the wireless user device populating anaddress book with the private identities obtained from the privateauthentication element.
 20. The method of claim 18, interactingcomprises interacting with a private GLMS.
 21. A wireless user deviceconfigured to perform the method of claim
 18. 22. A wireless user deviceof claim 21, configured to operate in a private mode and a regular mode.23. The wireless user device of claim 18, configured to encrypt theidentities.
 24. A computer readable medium with computer readable codestored thereon for implementing the method of claim
 18. 25. A carrierhalf-duplex processing element (CHDP) comprising: a first input forreceiving requests from a client device for a PoC session with at leastone private user device in response to which the CHDP generates anauthentication request for authentication of private identities ofprivate user devices; an output for sending the authentication requestto a private authentication element; a second input for receiving anauthentication response from the private authentication element; andwherein in the event of successful authentication, the CHDP invites theprivate user devices to participate in the PoC session and sets up ahalf-duplex communications session between devices that accept.
 26. Thecarrier half-duplex processing element of claim 25 wherein the CHDPcomprises a PoC server.
 27. The carrier half-duplex processing elementof claim 26 further comprising a GLMS, wherein the authenticationrequest is sent by the PoC server to the private authentication elementvia the GLMS server.
 28. The carrier half-duplex processing element ofclaim 27, wherein the authentication response is received by the PoCserver via the GLMS server.
 29. A system for authenticating privateusers from a private network when conducting PoC communications over acarrier network, the system comprising: a carrier processing elementconfigured to receive a request for a PoC session from a wireless userdevice, to send an authentication request of an identity of at least oneprivate invitee user device to a private authentication element, to sendan invitation for the PoC session to the at least one private inviteeuser device if an authentication is response received from the privateauthentication element, and to set up the PoC session between thewireless user device and the at least one private invitee user device;and a private authentication element configured to establishauthenticated identities of private user devices, to receive theauthentication request from the carrier processing element, toauthenticate the identities and to send the authentication response backto the carrier processing element indicating whether or not theidentities are authenticated.